After years of arguments, it looked, recently, as though we might be approaching a breakthrough in the debate over whether or not the world has been warming.

For the uninitiated, it might seem surprising that this is a subject of debate. Surely of all the questions about climate change – all the future modelling, mankind’s role in it – the one “Is the world warming up?” should be the easiest. After all, we presumably just have to wave a thermometer around and see what it says.

Obviously it’s much more complicated than that. Nasa’s Goddard Institute for Space Studies (GISS) has provided much of the data in recent years, and its figures have been vigorously disputed, for two reasons.

The second is that many of the measuring sites in other parts of the world are located in places that, Mr Watts and others believe, are artificially heated by human activity – by being close to parks, air conditioners, airports, that sort of thing. Mr Watts has started a second, volunteer-led project, surfacestations.org, to determine whether this has led to a bias towards warmer results than would otherwise be recorded.

It goes without saying that Mr Watts’s statement is indeed bold and entirely admirable: there is nothing more profoundly important in science than a willingness to change your mind as new facts come in.

However, Prof Muller’s appearance in front of the House has not had the desired effect for climate sceptics. Announcing the “preliminary” results of his team’s studies – based on a subset of the overall data, just two per cent, and therefore still very open to change – the findings showed “a global temperature trend that goes up and down with global cycles, and does so broadly in sync with the temperature records from other groups such as NOAA, NASA, and Hadley CRU.”

It is important to stress, again, that it is preliminary: as Best say, “the preliminary analysis includes only a very small subset (2%) of randomly chosen data, and does not include any method for correcting for biases such as the urban heat island effect, the time of observation bias, etc.“

But what is concerning is that Mr Watts, upon hearing that the preliminary results were not what he expected, seems to be rowing back from his pledge to accept the findings whatever they may be, describing Prof Muller’s testimony as “post normal science political theatre”. I don’t want to judge Mr Watts’s reaction yet – as he says, he is concerned because they are releasing the data early:

“There seems a bit of a rush here, as Best hasn’t completed all of their promised data techniques that would be able to remove the different kinds of data biases we’ve noted. That was the promise, that is why I signed on (to share my data and collaborate with them). Yet somehow, much of that has been thrown out the window, and they are presenting some results today without the full set of techniques applied.“ He goes on in a later post to suggest that the two per cent sampling are biased.

Of course, these are preliminary, as Prof Muller has been careful to say. But it’s hardly fair to blame this “theatre” on climate-change proponents: Prof Muller was called in as a witness by the (highly sceptical) House Republicans: as Best say on their website, “All of these results are preliminary, and the Berkeley Earth team would be more comfortable sharing them after they had been published in a peer-reviewed journal. However, Dr. Richard Muller was called to testify before congress on 31 March 2011. We did not solicit this presentation, but understand that congress needs our best testimony.”

I hope that, if the full results come out and support the earlier GISS/Nasa/CRU data, Mr Watts will change his mind, as he said. It’s just not very promising that he is already, apparently, trying to discredit it.

I know this will sound strange, but I do quite admire Anthony Watts: he is science literate, and therefore several rungs above some others on the sceptic side of the debate. And I have no doubt that he is far more knowledgeable than me on the subject. But compare him to George Monbiot, the enviromentalist and writer who has taken a hard look at a long-held belief of his – the dangerous nature of nuclear power – and found it lacking in evidence.

Here’s hoping that (should the evidence demand it) Mr Watts will have the courage to change his mind. It’s far too early to demand it of him yet, but when the final results come out (hopefully in the next few weeks or months – a paper is being submitted to the Bulletin of the American Meteorological Society), it will be interesting to see how Mr Watts, and other climate sceptics, respond.